Infrared Post-Cure of RIM Body Panels: A Significant Cost Savings

A new RRIM system produces a polyurea polymer that is capable of going through a traditional assembly process including E-coat bakes of up to 200C. In order to achieve the necessary performance characteristics, the high temperature resistant polyurea RIM polymer requires post-cure temperatures between 180C and 200C. Existing ovens are designed to post-cure materials below 160C. Also, existing ovens may not be large enough to handle pickup truck rear fenders. The existing ovens need to be refurbished or new ones built to meet the new market demand. To reduce the cost of the post-cure process, infrared (IR) radiation was tested to determine its utility for post-curing RIM parts. It was demonstrated that a infrared radiation can be used to pre-heat the RIM part in 1/10^th the time of a convection oven in the laboratory. The benefit of using infrared radiation is improved dimensional stability and impact properties with acceptable flexural modulus. Also, infrared pre-heating of RIM parts would reduce the overall length of the post-cure line, resulting in, less real estate to house an oven, fewer fixtures to hold parts through the post-cure process, and a more cost-effective oven.